Mixing apparatus



1965 w. H. DIXON ETAL 3,166,302

MIXING APPARATUS Filed Nov. 8, 1963 3 Sheets-Shoot 1 FIG.

WILL/AM HARRIS 0/x0- .WVENTORS' JOHN YANK/I/ICH ATTORNEY LEADING FIG. 5

FIG 2 Jan. 19, 1965 w. H. DIXON ETAL 3,166,302

MIXING APPARATUS LEADING EDGE WILL/AM HA RR/S o/xa/v WVENTORS' JOHNVANK/V/CH A TTORNEV LEAD/N6 EDGE Jan. 19, 1965 w, H. mxoN ETAL 3,166,302

MIXING APPARATUS Filed Nov. 8, 1963 3 Sheets-Sheet 3 WILL MM HARRIS0/x0/v JOHN m/vK/v/ch' A T TORNE Y Filed Nov. 8, 1963, Ser. No. 322,4553 Claims. (Cl. 259-108) This invention relates to the mixing of mortar,and in particular to a portable mixer for mixing cement for drywallconstruction. I

So-called dry wall or plasterboard construction has become anincreasingly widespread method for finishing the interior walls ofbuildings. This kind of construction is typically performed by securingdrywall sections to the studs or members that define the location of thewall, taping the seams between adjacent drywall sections, and finallyplastering or cementing the taped seams to obtain a wall surface havinga smooth,.unbroken appearance. The final cementing or plastering of thetaped seams is of utmost importance to the finished appearance of thewall, since any imperfections in the cemented seams are readilynoticeable. For this reason great care must be exercised in preparingthe drywall cement. The cement must be mixedin clean containers and inamost thorough manner to eliminate insofar as possible both foreignparticles and unmixed cement particles which would mar the finalappearance of the wall. 7

However, the proper mixing of drywall cement presents several problems.In the first place, the cement cannot be prepared in large quantities inadvance and stored, but

must be mixed in relatively small quantities on the job as needed inorder to obtain fresh cement of the proper quality and consistency.Second, thorough mixing by hand is time consuming and inefiicient.Third, electric power is not always available at remote constructionsites for the employment of electrical mixing tools. Finally. and mostimportant, although there are a number of well known portable devicesfor mixing mortar, for example, see F. 0. Skoog Patent 1,593,706,issuedluly 27,1916, and C. I. Tincher et a1. Patent 3,061,284, issuedOctober 30, 1962, none of them has been found to be suitable for mixingdrywall cement in relatively small quantities with the degree ofthoroughness necessary to eliminate virtually all unmixed cementparticles.

The present invention provides a portable mixer especially adapted formixing drywall cement efficiently, thoroughly, and in relatively smallquantities. Further, the portable mixer of the present invention issufficiently light in Weight and small in size so that it may be easilytransported by a single man, and it is powered by a small gasolineengine so that it may be employed at construction sites remote fromsources of electrical power.

In order to obtain thoroughly mixed drywall cement, this invention alsoprovides a stirrer especially adapted to mix thick, heavy mixtures ofrelatively high viscosity. There are a number of well known stirrersavailable, but as in the case of the paint stirrer described in R.Conley Patent 2,753,162, issued Iuly 3, 1956, the prior art stirrers aregenerally not capable of mixing cement with the thoroughness required indrywall construction.

The stirrer of this invention is provided with two pairs of verticallyspaced horizontal blades oriented in opposite directions on either sideof a vertical shaft in order to agitate cement particles lying in strataat the top and bottom of the container and to direct cement particles inthese strata toward the center of the container. Further,

United States Patent the stirrer is provided with two pairs ofhorizontally "ice particles at the center of the container; and an outerpair of vertical blades secured to the horizontal blades and oriented ata predetermined angle to direct cement particles from the walls of thecontainer to the center of the container.

The invention will be fully understood from the followingdetaileddescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a perspective view of portable mixing apparatus embodying theprinciples of this invention;

FIG. 2 is a front elevation view of the stirrer of this invention;

FIG. 3 is a side elevation partially in section of the stirrerillustrated in FIG. 2; a

FIG. 4 is another side elevation partially in section of the stirrershown in FIG. 2; and

FIG. 5 is a bottom plan view in section of the stirrer shown in FIG. 2.

Referring first to FIG. 1, this drawing illustrates a complete portablemortar mixing apparatus embodying the principles of the presentinvention. A conventional gasoline engine 1, for example, an engine ofabout two horsepower, is secured to and supported upon a horizontal baseplate 11, and the output shaft of engine 1 is connected by drive wheel2, belt 3, and pulley wheel 4 to the input shaft of a speed reducingmechanism 5, which may be a worm and gear reducer of conventionaldesign. Reducer 5 is also secured to platform 11, and the output shaftof reducer 5 extends vertically through platform 11 to chuck 15 which isconnected to the vertical rotatable drive shaft 18 of the stirrer 17 ofthe present invention.

It has been found that a suitable rotation speed for stirrer 17 is onthe order of revolutions per minute, so that the ratio of reducer 5 andthe relative sizes of drive wheel 2 and pulley wheel 4 are selected toconvert the speed of engine 1 to this desired speed of rotation; forexample, if engine 1 has an output speed of 3,600 revolutions perminute, reducer 5 may be selected to have a ten to one speed reductionratio, and drive wheel 2 and pulley wheel 4 may be chosen to effect atwo to one reduction ratio in order to obtain an overall twenty to onereduction ratio, thereby to drive stirrer 17 at a rotation speed of 180revolutions per minute.

The complete mixing apparatus described above is sufficiently light inweight that it may be lifted by a single man by means of handles 10a.However, the mixing apparatus may be employed in a stationary positionby placing the apparatus upon a suitable portable stand 12 provided withlegs 13 of appropriate height for inserting stirrer 17 into container 16at the proper level: It is observed in FIG. 1 that stand 12 issubstantially narrower than platform 11 in order for chuck 15 andvertical shaft 18 to move freely. Also, in order to prevent motion ofthe mixer on stand 12 due to engine vibration, one or more pairs ofmating studs 14a and holes 1412 are respectively provided in stand 12and platform 11.

In order tooperate the mixing apparatus, the engine 1 is started and thestirrer 17 is lowered into cylindrical container 16 within which therehas been previously placed cement ingredients in the desired andappropriate proportions. By depressing the engine throttle (not shown),the automatic engine clutch (also not shown) is engaged, therebyrotating stirrer 17 through the linkage described above. After thecement in container 16 has been thoroughly mixed, the stirrer 17 isstopped by re leasing the engine throttle, the mixer is lifted to raisestirrer 17 out of container 16, and,container 16 may then be carried toany desired location.

Turning now to FIG. 2, this drawing illustratesthe structure of thestirrer of this invention. It is to be noted at this point that thestructure of the stirrer of this invention is specifically designed formixing drywall cement areasee in a cylindrical container ofsubstantially uniform diameter, as shown by container 16 in FIG. 1.

At diametrically opposite points on the lower end of vertical shaft 18are welded or otherwise secured a pair of horizontal blades 23a and 23b,and in coplanar, vertically spaced relation from the lower end of shaft18 another pair of horizontal blades 24a and 24b are also welded atdiametrically opposite points on shaft 13. Horizontal blades 23a, 23bare respectively secured to shaft 13 at relatively small angles of equalmagnitude but opposite orientation, for example, '10 to 20 degrees is asuitable magnitude, so that the leading edges of blades 23a, 23b areinclined toward the upper end of shaft 318, as shown in F168. 3 and 4,thereby directing cement particles from the bottom of the container tothe center of the container. Similarly, the pair of horizontal blades24a, 24b is also secured to shaft 18 at a small angle so that theleading edges of blades 24a, 24b are inclined toward the bottom of shaft18, thereby directing cement particles from the top of the container tothe center of the container.

Between each of the pairs of horizontal'blades there is secured, forexample, by welding, two pairs of vertical blades in spaced relation toeach other, an inner pair of vertical blades 22a and 22b, and an outer,pair of vertical blades 21a and 21b. As shown in FIG. 5, each of theinner vertical blades 22a, 22b is parallel to and offset from an axis AApassing through the center of shaft 13 and parallel to theleading edgesof horizontal blades 24a,'24b, so that each vertical blade 22a, 22b isset nearer the leading edges of the respective horizontal blades 23a,24a, and 23b, 24b, between which each vertical blade is secured. Theouter vertical blades 21a, 21b are parallel to each other, and as shownin FIG. 5, each outer vertical blade is inclined at a predeterminedangle with respect to a vertical plane perpendicular to plane AA, forexample, at an angle on the order of 10 to 20 degrees. As shown in thedrawings each of the inner vertical blades 22a, 22b is approximatelyequidistant from the vertical shaft 18 and the respective outer verticalblades 21a, 21b.

The arrangement of the vertical blades also contributes to the thoroughmixing required for drywall cement, particularly the inner pair ofoffset vertical blades 22a and 22b which constantly agitate the mixturein the center of the container. This structural feature of providing aninner pair of vertical blades is indispensable for properly andthoroughly mixing heavy, dense mortars of the type exemplified bydrywall cement. Also, by making the combined horizontal extension, W, ofthe two pairs of horizontal blades equal, there is obtained equalamounts of agitation at bothtthe top and bottom of the cement mixture inthe container, thereby producing the thorough mixing required fordrywall cement. By appropriately moving the mixing apparatus, the outer.pair of vertical blades 21a, 21b may be made to scrape the inner wall ofcontainer 16 to prevent the accumulation ofunmixed cement particles onthe container Wall, and similarly the lower pair of horizontal blades23a, 23b may be made to scrape the bottom of container 16 to preventtheaccumulation of unmixed cement particles at the bottomof container 16.

Although this invention has been described in terms of mixing drywallcement, it is to be understood that the present invention may be usedfor mixing other kinds of dense cement and mortar. It is to be furtherunderstood that the stirrer of the present invention may be employed inmixing apparatus other than the above-described embodiment by thoseskilled in the art without departing from the spirit and scope of theinvention.

What is claimed is: V

1. Apparatus for mixing drywall cement in a cylindrical container whichcomprises 7 a rotatable vertical shaft provided with an upper end and alower end,

a first pair of first and second horizontal blades vertically spacedfrom said lower end of said vertical shaft and respectively secured atfirst and second I predetermined angles of equal magnitude but oppositeorientation to diametrically opposite points on said vertical shaft sothat the leading edges of said first horizontal blade and said secondhorizontal blade are respectively-inclined at said first and secondpredetermined angles toward said upper end of said vertical shaft,wherein the combined horizontal extension of said first pair ofhorizontal blades is smaller than said uniform diameter of saidcylindrical container,

a second pair of third and fourth horizontal blades coplanar with saidfirst pair of horizontal blades and respectively secured atcorresponding third and fourth predetermined angles of equal magnitudebut oppo site orientation to diametrically-opposite points on said lowerend' of said vertical shaft so that said first and third horizontalblades are vertically spaced from one another and said second and fourthhorizontal blades are vertically spaced from one another,

wherein the leading edges of said third and fourth horizontal blades arerespectively inclined at said third and fourth predetermined anglestoward said lower end of said vertical shaft, and the combinedhorizontal extension of said second pair of horizontal blades is equalto the combined horizontal extension of said first pair of horizontalblades,

a first pair of first and second vertical blades horizontally separatedfrom one another by a spacing equal to said combined horizontalextensions of said first and second pairs of horizontal blades andsecured between said first and second pairs of horizontal blades,wherein said first vertical blade is secured between said first andthird horizontal blades so that the leading edge of said first verticalblade is parallel to and inclined away from said vertical shaft, andsaid second vertical blade is secured between said second and fourthhorizontal blades so that said second vertical blade is parallel to saidfirst vertical blade,

a second pair of third and fourth horizontally separated vertical bladessecured between said first and second pairs of horizontal blades,wherein said third vertical blade is secured between said first andthird horizontal blades at a horizontal spacing equidistant from saidvertical shaft and said first vertical blade, and said fourth verticalblade is secured between said second and fourth horizontal blades at ahorizontal spacing equidistant from said vertical shaft and said secondvertical blade, and each of said third and fourth vertical blades isparallel to and offset in opposite directions from a vertical axispassing throughthe center of said vertical shaft and parallel to theleading edges of said first and second pairs of horizontal blades sothat said third vertical blade is parallel to and nearer the leadingedges of said first and third horizontal blades and said fourth verticalblade is parallel to and nearer the leading edges of said second andfourth horizontal blades.

2. A portable mixer for mixing a plurality of ingredients in thepreparation of mortar in a cylindrical container having a uniformhorizontal diameten'said mixer comprising horizontal support meansprovided with an upper surface and a lower surface,

a source of power secured to said upper surface of said horizontalsupport means and provided with an output shaft,

a speed reducing means secured to said upper surface of said horizontalsupport means and provided with an output shaft that extends verticallythrough said horizontal support means and an input shaft,

means for connecting said output shaft of said source of power to saidinput shaft of said speed reducing means,

a rotatable vertical shaft provided with an upper end and a lower end,

means for connecting said upper end of said vertical shaft to saidoutput shaft of said speed reducing means, and

stirring means secured to said lower end of said vertical shaft, saidstirring means including a first pair of first and second horizontalblades vertically spaced from said lower end of said vertical shaft andrespectively secured at a predetermined angle to diametrically oppositepoints on said vertical shaft so that the leading edges of said firsthorizontal blade and said second horizontal blade are inclined at saidpredetermined angle toward said upper end of said vertical shaft,wherein the combined horizontal extension of said first pair ofhorizontal blades is smaller than said uniform diameter of saidcylindrical container,

a second pair of third and fourth horizontal blades coplanar with saidfirst pair of horizontal blades and respectively secured atcorresponding third and fourth predetermined angles of equal magnitudebut opposite orientation to diametrically opposite points on said lowerend of said vertical shaft so that said first and third horizontalblades are vertically spaced from one another and said second and fourthhorizontal blades are vertically spaced from one another, wherein theleading edges of said third and fourth horizontal blades arerespectively inclined at said third and fourth predetermined anglestoward said lower end of said vertical shaft, and the combinedhorizontal extension of said second pair of horizontal blades is equalto the combined horizontal extension of said first pair of horizontalblades,

a first pair of first and second vertical blades horizontally separatedfrom one another by a spacing equal to said combined horizontalextensions of said first and second pairs of horizontal blades andsecured between said first and second pairs of horizontal blades,wherein said first vertical blade is secured between said first andthird horizontal blades so that the leading edge of said first verticalblade is parallel to and inclined away from said vertical shaft, andsaid second vertical blade is secured between said second and fourthhorizontal blades so that said second vertical blade is parallel to saidfirst vertical blade,

a second pair of third and fourth horizontally separated vertical bladessecured between said first and second pairs of horizontal blades,wherein said third vertical blade is secured between said first andthird horizontal blades at a horizontal spacing equidistant from saidvertical Shaft and said first vertical blade and said fourth verticalblade is secured between said second and fourth horizontal blades at ahorizontal spacing equidistant from said vertical shaft and said' secondvertical blade, and each of said third and fourth vertical blades isparallel to and offset in opposite directions from a vertical axispassing through the center of said vertical shaft and parallel to theleading edges of said first and second pairs of horizontal blades sothat said third vertical blade is parallel to and nearer the leadingedges of said first and third horizontal blades and said fourth verticalblade is parallel to and nearer the leading edges of said second andfourth horizontal blades,

3. Apparatus as defined in claim 2 wherein said source of powercomprises a portable gasoline engine.

References Cited by the Examiner UNITED STATES PATENTS 1,458,855 6/23Sargent 259-1 2,035,333 3/36 Mills 259134 2,441,727 5/48 Snow 259l08 X2,521,384 9/50 Marienthal.

2,753,162 7/56 Conley 259134 2,898,093 8/59 Severson.

3,087,708 4/63 Sims 259-1 CHARLES A. WILLMUTH, Primary Examiner.

1. APPARATUS FOR MIXING DRYWALL CEMENT IN A CYLINDRICAL CONTAINER WHICHCOMPRISES A ROTATABLE VERTICAL SHAFT PROVIDED WITH AN UPPER END AND ALOWER END, A FIRST PART OF FIRST AND SECOND HORIZONTAL BLADES VERTICALLYSPACED FROM SAID LOWER END OF SAID VERTICAL SHAFT AND RESPECTIVELYSECURED AT FIRST AND SECOND PREDETERMINED ANGLES OF EQUAL MAGNITUDE BUTOPPOSSITE ORIENTATION TO DIAMETRICALLY OPPOSITE POINTS ON SAID VERTICALSHAFT SO THAT THE LEADING EDGES OF SAID FIRST HORIZONTAL BLADE AND SAIDSECOND HORIZONTAL BLADE ARE RESPECTIVELY INCLINED AT SAID FIRST ANDSECOND PREDETERMINED ANGLES TOWARD SAID UPPER END OF SAID VERTICALSHAFT, WHEREIN THE COMBINED HORIZONTAL EXTENSION OF SAID FIRST PAIR OFHORIZONTAL BLADES IS SMALLER THAN SAID UNIFORM DIAMETER OF SAIDCYLINDRICAL CONTAINER, A SECOND PAIR OF THIRD AND FOURTH HORIZONTALBLADES COPLANAR WITH SAID FIRST PAIR OF HORIZONTAL BLADES ANDRESPECTIVELY SECURED AT CORRESPONDING THIRD AND FOURTH PREDETERMINEDANGLES OF EQUAL MAGNITUDE BUT OPPOSITE ORIENTATION TO DIAMETRICALLYOPPOISTE POINTS ON SAID LOWER END OF SAID VERTICAL SHAFT SO THAT SAIDFIRST AND THIRD HORIZONTAL BLADES ARE VERTICALLY SPACED FROM SAIDANOTHER AND SAID SECOND AND FOURTH HORIZONTAL BLADES ARE VERTICALLYSPACED FROM ONE ANOTHER, WHEREIN THE LEADING EDGES OF SAID THIRD ANDFOURTH HORIZONTAL BLADES PREDETERMINED ANGLES TOWARD SAID THIRD ANDFOURTH PREDETERMINED ANGLES TOWARD SAID LOWER END OF SAID VERTICALSHAFT, AND THE COMBINED HORIZONTAL EXTENSION OF SAID SECOND PAIR OFHORIZONTAL BLADES IS EQUAL TO THE COMBINED HORIZONTAL EXTENSION OF SAIDFIRST PAIR OF HORIZONTAL BLADES, A FIRST PAIR OF FIRST AND SECONDVERTICAL BLADES HORIZONTALLY SEPARATED FROM ONE ANOTHER BY A SPACINGEQUAL TO SAID COMBINED HORIZONTAL EXTENSIONS OF SAID FIRST AND SECONDPAIRS OF HORIZONTAL BLADES AND SECURED BETWEEN SAID FIRST AND SECONDPARIS OF HORIZONTAL BLADES, WHEREIN SAID FIRST VERTICAL BLADE IS SECUREDBETWEEN SAID FIRST AND THIRD HORIZONTAL BLADE SO THAT THE LEADING EDGEOF SAID FIRST VERTICAL BLADE IS PARALLEL TO AN INCLINED AWAY FROM SAIDVERTICAL SHAFT, AND SAID SECOND VERTICAL BLADE IS SECURED BETWEEN SAIDSECOND AND FOURTH HORIZONTAL BLADES SO THA SAID SECOND VERTICAL BLADE ISPARALLEL TO SAID FIRST VERTICAL BLADE, A SECOND PAIR OF THIRD AND FOURTHHORIZONTALLY SEPARATED VERTICAL BLADES SECURED BETWEEN SAID FIRST ANDSECOND PAIRS OF HORIZONTAL BLADES, WHEREIN SAID THIRD VERTICAL BLADE ISSECURED BETWEEN SAID FIRST AND THIRD HORIZONTAL BLADES AT A HORIZONTALSPACING EQUIDISTANT FROM SAID VERTICAL SHAFT AND SAID FIRST VERTICALBLADE, SAID SAID FOURTH VERTICAL BLADE IS SECURED BETWEEN SAID SECONDAND FOURTH HORIZONTAL BLADES AT A HORIZONTAL SPACING EQUIDISTANT FROMSAID VERTICAL SHAFT AND SAID SECOND VERTICAL BLADE AND EACH OF SAIDTHIRD AND FOURTH VERTICAL BLADES IS PARALLEL TO AND OFFSET IN OPPOSITEDIRECTIONS FROM A VERTICAL AXIS PASSING THROUGH THE CENTER OF SAIDVERTICAL SHAFT AND PARALLEL TO THE LEADING EDGES OF SAID FIRST ANDSECOND PAIRS OF HORIZONTAL BLADES SO THAT SAID THIRD VERTICAL BLADE ISPARALLEL TO AND NEARER THE LEADING EDGES OF SAID FIRST AND THIRDHORIZONTAL BLADES AND SAID FOURTH VERTICAL BLADE IS PARALLEL TO ANDNEARER THE LEADING EDGES OF SAID SECOND AND FOURTH HORIZONTAL BLADES.